Spark-plug-testing device



H Aug. 26, 1930. cu. KERTESZ SPARK PLUG TESTING DEVICE Filed June 25, 1927 2 Sheets-Sheet l INVENTOR flmgfaf/flf/rrfsz f Law TORNEY .Aug. 26,1930.

C./J. KERTES 'Z'.

SPARK-PLUG TESTING DEVICE Filed June 25, 1927 2 Sheets-Sheet 2 Cam/ J hi /771552 Patented Aug. 26, 1930 i I UNITED STATES PATENT i f CHARLES J. KERTESZ, F SEATTLE, WASI-IINGTO1\T SPARK-PL'UG-TESTINGDEVICE Application filed June 25, 1927. Serial No. 201,512.

This invention relates to means for testing plug tester embodied by the present inven' spark plugs, ignition coils and the like, and tion. v 1, has for its principal object to provide a test- Figure 2 is a diagrammatic view of the ing device whereby the spark plugs may be testing circuit connections and wiring.

tested under compression. Heretofore, many Figure 3 is a detail, sectional view of the devices have been made for'testing' spark compression cylinder in which the plugs'are plugs but none, to my knowledge, has been mounted for testing and its connections for provided for testing under compression, but admitting air pressure thereto.

on the contrary, test under ordinary atmos- Figure i'is a side view of the device,

. 0 pheric pressure. It very frequently happens showing the spark plug holder in section and that a spark plug will pass a very satisfactory with the spark plug in position for testing. test when in atmospheric pressure but will Figure 5 is an end view of the device as fail entirely when placed under working conshown in Figure 1. c ditions; this being due to the fact that when Referring more in detail to thedrawings- 15 actually in use theyare under high compres- 1 designates a flat, rectangular base plate 5 sion t th ti th Spark i du d, on which a coil box'Q is mounted, and 3 desig- In view of the above, it has been the object nates a step-down transformer of any desirof this invention to provide means whereby able character whereby an electric circuit, spark plugs may be tested under comprcswhich may be the usual city lighting circuit,

sion to the same degree, or greater, than of 110 volts, may be reduced to a six-volt 7 that to which they are'subjected when placed circuit,,or to-a circuit which is suitable for under working conditions in an engine, and the present purpose. v p to so construct the testing device thatthe re As is illustrated diagrammatically in sults may be visibly observed. Figure 2, the transformer comprises apri- 25 More specifically stated, it is the object of mary winding 5 which is connected at its ends this invention to provide a testing device as' with the supply, or city circuit, and a secabove stated, comprising a pressure chamber ondary winding 6 which is connected at its into which the sparking end of the plug to ends with the opposite ends of the primary be tested may be threaded and which'is prowinding 7 of the testing circuit embodied-in 30 vided with a glass panel through which the the coil box; one of these connections being course and intensity of the spark may be 'ob-. made through a normally open switch mechserved when a circuit is closed through the anism which will presently be described. plug, the chamber also being provided with The sccondarywinding8 of thetestingcirmeans for admitting air under pressure there cuit is grounded at one end to the metallic to to any desired degree and for retaining base plate 1 and at its other end connects, by

' it during a test. V means of a scre'w 9 or binding post, with a Another object of the invention is toprocontact plate 10 that is mounted, by meansof vide a switch mechanism for the testing cirthe screwofn an insulator 11, on top of the Y cuit which closes automatically incidental to box 2. Y i

40 the adjustment of the plug to testing posi- Supported atone side'of thecoil box and 9 tion. resting at its lower end against thebase plate Other objects of the invention reside in the 1 to provide an electrical connection, is a various details of construction, combination metal standard,,or tube, 14 provided at its of parts and in the mode-of operation of the upper end with a pipe fitting 15 with which device as is hereinafter described. a pipe 17 leading from a source of air under In accomplishing these objects, I have propressure is connected; this pipe 17 being vided the improved details of construction, equipped with a control valve 18. A presthe preferredforms of which are illustrated sure gauge 19 is also connected with the top in the accompanying drawings, whereinof the fitting 15, by means of a. pipe 20, and 59 Figurel is a perspective View of a spark extending horizontally from the fitting and tact plate and screw 9.

One end of the compression cylinder 23 is equipped with a cap 25 having a threaded central opening 26 through which the end of a'spark plug, as designated at 16, to be tested ma be threaded, and the other end of the cylin er is tightly closed by means of a glass panel 27 that is held in place by a clamping collar 28 threaded onto the cylinder. The glass panel is provided in order that a person making the test may see the inner end of the spark plug while a test is being made and may observe the intensity and course of the spark or ascertain whether or not a spark is produced.

Fixed relative to the cylinder 23 about the pipe connection 22, is a lever 30 having an extended handle by means of which the cylinder may be rotated on its mounting to bring the outer end of the central contact 16 of the spark plug from and against the plate 10. The inner end of the lever has a short extension 30' and this is connected, through a tension spring 32, with the upper end of a vertically disposed switch rod 33 that is mounted slidably in guides 34 fixed on the side of the coil box. The lower end of this rod is ex tendedthroug'h an insulating block 35 fixed on the under side of the base 1 and it is equipped with a flat switch contact 36 adapted to be pulled against contacts 37 and 38 mounted on the block and through which a circuit through the primary winding of the testing circuit is closed. This induces the high tension testing circuit through the secondary winding 8.

Assuming the device to be so'constructed, it is used as follows: The spark plug to be tested is threaded into the end of the pressure cylinder 23 and then the valve 18 is opened to admit air to a desired pressure into the cylinder. The lever 30 is then actuated downwardly so as to. rotate the cylinder in such manner as to bring the outer end of the central contact 16 of the spark plug against the plate 10, as in Figure 4:. At the same time the switch rod 33 is moved upwardly and closes a circuit through the primary winding 7 of the testing coil, and this induces a the current through the secondary winding and through the spark plug. By observation through the glass panel of the pressure cylinder, the condition'of the spark plug may be determined; that is, the observer may see whether or not any spark passes the terminals, or whether the circuit is grounded through the plug due to carbon, defective insulators, or for other reasons. Air may be admitted to the cylinder to any desired pressure, and this pressure determined by reference to the gauge 19. With this device it is possible for the person making the test to observe the course of the spark and just at what pressure it ceases. It is also possible to detect faulty insulation and short circuits.

The switch mechanism here provided, being connected with the lever 30. automatically opens the testing circuit as soon as the plug is adjusted away from the contact 10 by upward swinging of the lever 30.

To provide for testing plugs of various lengths, the contact plate 10 is of considerable length and curves downwardly toward the housing 2and comes to a point. Also, to provide a safety gap across which the testing circuit may jump in the event resistance through the plug is too great, I have threaded a screw 40 in the topof the housing 2 di rectly below the point of plate 10; the length of the gap being adjustable by threading the head of the screw onto or away from the point of the plate 10. This screw is con nected in the secondary winding 8, as shown in Figure 2.

While the device is illustrated as for testing spark plugs, it may also be used for testing any similar device which may be used in like manner for producing a spark in an internal combustion engine. Also, it is very useful for testing the output of ignition coils by connecting the latter in the secondary circuit 8 between the spark plug terminal 16 and the contact plate 10.

t is to be understood also that various testin mediums other than air may be used in the cylinder for the reason that various gases may be more desirable for making tests in some instances.

Since it is readily apparent that various changes in the details of construction could be made without departing from the spirit of the invention, I do not desire the claims to be limited only to the device as herein shown but to cover broadly a means for testing a spark plug, or other ignition device, under pressure.

Having thus described my invention, what I claim as new therein and desire to secure by Letters Patent, is:

1. A device of the character described comprising an adjustably supported pressure chamber within which a testing medium may be maintained under pressure, means for mounting a spark plug in position for testing in the chamber, a fixed contactand a testing circuit connected with the contactand with the pressure chamber and adapted to be closed through the plug or opened by adjustment of the pressure chamber that brings the outer end terminal of the plug against or from the fixed contact.

2. A device of the character described comprising a rotatably mounted pressure cylinder, means for admitting a pressure medium thereto, an opening in the cylinder for mountagainst and from which the a lever fixed ing a spark plug with its sparking terminals exposed to the pressure, a transparent wall in the cylinder through which the terminal end of the plug may be observed, a fixed contact, a testing circuit connected with the contact and with the pressure cylinder and means for rotatably moving the cylinder to press the outer terminal of a plug mounted therein from or against the contact.

3. A device of the character described comprising a rotatably mounted pressure cylinder, means for admitting a pressure medium thereto, an opening in the cylinder for mounting a spark plug with its sparking terminals exposed to the'pressure, a transparent wall in the cylinder through which the terminal end of the plug may be observed, a fixed contact, a testing circuit connected with the contact and with the pressure cylinder and means for rotatably moving the cylinder to press the outer terminal of a plug mounted therein from or against the contact, and a circuit control switch operable from open to closed positions by movement ofthe cylinder which brings the spark plug terminal against or from the fixed contact.

4:. A spark plug testing device comprising a pressure cylinder, a pipe rotatably supporting the cylinder having connection with a pressure medium, a control valve in the pipe, an opening in ing a spark plug, a glass panel in the cylinder through which the sparking terminals of the plug may be observed, a fixed contact outer terminal of the spark plug may be engaged by rotatable movement of the cylinder, having connection with the contact and with the cylinder, a control switch for the circuit, to the cylinder whereby it may be adjusted and means connecting the lever and switch for closing the latter when the spark plug terminal is brought against the contact plate.

Washington, this 16th Signed at Seattle, day of June, 1927.

, CHARLES J. KERTESZ.

the cylinder for mount-Ye a testing circuit 

